The research of JSP duplicate submission

JSP summary of issues in which pages cannot be refreshed or prevented from refreshing<1> If you want the form to refresh when you select, delete, modify, and so on, you need to add: window.returnvalue=0. such as leadership/leader_ctl.jsp

< body LeftMargin = "0" topmargin = "0" > <%@ page contentType = "text/html;         charset=gb2312 "language =" java "import =" java.sql.* "ErrorPage =" "%> <%@ page import =" leader.* "%> <% Leaderbean leader=NewLeaderbean ();     String struserid=request.getparameter ("Key");     Session.setattribute ("Employuserid", strUserID); System.out.println ("strUserID:" +struserid);if(leader.        Postedit (Request)) {//system.out.println ("me5"); Out.println ("<script>window.returnvalue=0;window.close ();</script>"); return; }Else{if(Request.getparameter ("Oper")!=NULL){if(Request.getparameter ("Oper"). Equals ("Delleader")) {out.println ("<script>alert" +leader).             lastopermsg+ "');window.returnvalue=0;</script>");         Return }if(Request.getparameter ("Oper"). Equals ("Setleader"))              {//system.out.println ("Me3"); Out.println ("<script>alert" ("+leader").             lastopermsg+ "'); Window.returnvalue=0;window.close ();</script>");             System.out.println ("Me4");         Return }if(Request.getparameter ("Oper"). Equals ("Delcompetence"))              {////system.out.println ("strUserID:" +struserid); Out.println ("<script>alert" ("+leader").             lastopermsg+ "'); History.back ();</script>");             System.out.println ("Me4");         Return }if(Request.getparameter ("Oper"). Equals ("Addcompetence"))              {//system.out.println ("AddCompetence1"); Out.println ("<script>alert" ("+leader").             lastopermsg+ "'); History.back ();</script>");             System.out.println ("AddCompetence2");         Return }Else{if(Request.getparameter ("Oper"). Equals ("QX")) {out.println ("<script>alert" +leader).               lastopermsg+ "'); Window.returnvalue=0;window.close ();</script>");            Return }Else{//system.out.println ("Me6"); Out.println ("<script>alert" ("+leader").                lastopermsg+ "'); Window.close ();</script>");            Return }//3e}}}%>

<2> If you require automatic refresh from the server at intervals, add: (1) Method: <%response.setheader ("Refresh", "");%>
15 Wonderful Refresh once (2) method: automatically refresh Web pages
By adding the following code to and from the HTML, the page that you are browsing after 5 minutes will automatically change to target.html. The delay time, in seconds, for the refresh of 300 in the code. Targer.html for the target page you want to turn to, if this page is the automatic refresh this page. <meta http-equiv= "Refresh" content= "300; Url=target.html "> (3) Method: Demo Effect: This page will automatically refresh at the specified time, code hint: Copy the following code to the 〈head〉 area

<script> <!--var limit= "0:15"//Modify Refresh time if (document.images) {var parselimit=limit.split (":") parselimit=parse LIMIT[0]*60+PARSELIMIT[1]*1} function Beginrefresh () {if (!document.images) return if (parselimit==1) Window.location.reload () else{parselimit-=1 Curmin=math.floor (PARSELIMIT/60) cursec=parselimit%60 if (curmin!=0) curtime=curmin+ "+cursec+" seconds and then brush the page again. "Else curtime=cursec+" seconds to brush this page again. "Window.status=curtime settimeout (" Beginrefresh () ", 1000)} Window.onload=beginrefresh//--> </script>

<2> to prevent automatic refresh from the server, you need to add:

<%@ page contenttype= "text/html;charset=gb2312"%><%@ page language= "java" import= "java.io.*"%>< Html>

Programme 2

J J SP counter, the same computer 10 seconds to prevent refreshing<%@ page contenttype= "text/html; charset=gb2312 "language=" java "import=" java.sql.* "errorpage=" "%>" <! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "HTTP://WWW.W3.ORG/TR/HTML4/LOOSE.DTD" > <meta http-equiv= "Content-type" content= "text/html; charset=gb2312 "> <meta name= "generator" http-equiv= "Refresh" > <title> Untitled Document </title> <link href= "Css/counter.css" rel= "stylesheet" type= "Text/css" > <body bgcolor= "#FFFFFF" > <!--start counter--> <div align= "center" > <%@ page import= "Com.ckj.counter.*,java.io.*,java.util.date"%> <%counter ct=new Counter (); String count= "0"; String counterid= "0"; try{ String Strdirpath = new File (Application.getrealpath (Request.getrequesturi ()). GetParent (); System.out.println ("The absolute path of the directory:" + Strdirpath + "<br/>"); String strFullPath = Session.getservletcontext (). Getrealpath ("/"); System.out.println (strFullPath); ct.path=strfullpath+ "/counter/count.txt"; 1 Session Store time value, 2 Next time Compare if (Session.getattribute ("Counttime") ==null) {//if the initial visit Count=ct.docount (); SYSTEM.OUT.PRINTLN ("--------calculation--------" +system.currenttimemillis ()); Session.setattribute ("Counttime", String.valueof (System.currenttimemillis ()));} Else {//If the refresh interval exceeds System.out.println ("--------Refresh Difference--------" + (System.currenttimemillis ()-L